1. Field of the Invention
The present invention relates to a lamp unit of a vehicle headlamp configured to emit direct emitting light from a light source arranged rearward from a convex lens to deflect toward a front side by the convex lens arranged on an optical axis extending in a front and rear direction of the lamp unit.
2. Related Art
In a background art, as a lamp unit of a vehicle headlamp, as described, for example in JP-A-2005-044683, there is known a so-to-speak direct emitting type lamp unit for emitting direct light from a light source arranged rearward of a convex lens to deflect toward a front side by the convex lens arranged on an optical axis extending in a front and rear direction of the lamp unit.
Further, JP-A-2005-108555 describes such a direct emitting type lamp unit in which a convex lens thereof is constituted to emit direct light from a light source as substantially parallel light in a vertical face and emit the direct light as light diffused to left and right sides in a horizontal face.
By adopting the lamp unit of JP-A-2005-108555, a laterally elongated light distribution pattern can be formed. When the laterally elongated light distribution pattern is formed at a vicinity of a lower side of a cutoff line in a light distribution pattern for a low beam, a road face on a front side of a vehicle can be irradiated widely in a width thereof.
However, even when such a constitution is adopted, the following problem is posed.
That is, in order to be able to ensure a front optical recognizability of a driver of a vehicle without casting glare to a driver running on an opposed lane in the low beam, the cutoff line of the light distribution pattern for the low beam is formed such that a cutoff line on a side of own lane is stepped up or extended in a skewed upper direction relative to a cutoff line on a side of the opposed lane. Therefore, by only forming the laterally elongated light distribution pattern simply at the vicinity of the lower side of the cutoff line of the light distribution pattern for the low beam, although the vehicle front side road face can be irradiated widely in the width, a region on a side of the own lane cannot be irradiated remotely. Therefore, there poses a problem that a remote optical recognizability cannot sufficiently be promoted by the low beam.